Into a cosmetic preparation, various powders such as an inorganic powder, an organic powder, and a coloring powder are incorporated for the purpose of providing a make-up effect and retentivity thereof and adjusting the touch. However, since inorganic powders are especially poor in compatibility with skin due to a nature of inorganics, a cosmetic preparation with an inorganic powder incorporated therein is poor in spreading on skin and gives strong squeaky feel, whereby physical irritation to skin is caused and smoothness during application is impaired. Furthermore, because of high aggregation property and low oil dispersibility of the particles, an inorganic powder has lowered long-term storage stability, make-up effect, UV absorption effect, and the like of the cosmetic preparation. For solving the problems, the surface of the powder has conventionally been treated with various surface treating agents. For example, a number of methods such as methods of surface treatment with an ester oil, a metal soap, lecithin, a silicone oil (see, for example, PTLs 1 and 2), a perfluoroalkyl oil (see, for example, PTLs 3 and 4), and the like are known.
However, although a powder surface-treated with an ester oil, a metal soap, a silicone oil, a perfluoroalkyl oil, and the like has smooth touch and is lowered in physical irritation to skin, such a powder is poor in affinity with a living body, and therefore has not been satisfactory in compatibility with skin. In addition, in order to achieve good touch and enhance the compatibility with skin, techniques of using an acylated amino acid (see, for example, PTLs 5 and 6) and techniques of using an acylated polypeptide obtained by acrylating a polypeptide which is a polymer of an amino acid (see, for example, PTLs 7 and 8) are known, but the effects thereof have not been satisfactory.
Although a cosmetic preparation which has good usability and touch and also shows high cosmetic retentivity has been conventionally demanded, it is not easy to satisfy both the requirements. In particular, in a powdery cosmetic preparation, when it is intended to enhance too much the adhesion to skin in pursuit of cosmetic retentivity, the powdery cosmetic preparation has a tendency to reduce smooth spreading and deteriorate usability and use feeling. In addition, uniform formation of cosmetic-film is also required, but it is difficult in practice to provide a cosmetic preparation satisfying all the requirements.
Among the demands of consumers regarding the cosmetic retentivity, there is a demand to prevent elimination of cosmetic-film due to secondary adhesion (a phenomenon that the cosmetic-film is broken up and eliminated due to a hand, handkerchief and face mask coming into contact with skin after application of the cosmetic preparation). However, in a cosmetic preparation which is enhanced merely in adhesion to skin, it has been difficult to also prevent the adhesion to hands or clothes. In order to prevent the secondary adhesion, for example, a technique of using an organic silicone resin (PTL 9), a technique of using a powder surface-treated with a specific film forming agent (PTL 10), and a technique of incorporating a boron nitride powder and a coating agent (PTL 11) are known. The techniques are however not fully satisfactory in the effect and the touch in use.